← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 144 · 40 questions
TalentJR

How to do it in your head (Guess, divide, average): Division: round the divisor to the nearest ten and find the closest multiple of it. Square root: guess the nearest whole root, then divide the number by your guess. Average the guess and the answer of the division, and round to 1 decimal place.

NameDateTime takenScore ___ / 40
  1. 1.√63 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 8.1 (d) 7.9
  2. 2.Best estimate of 1937 ÷ 46? (a) 3900 (b) 39 (c) 390
  3. 3.Best estimate of 1313 ÷ 24? (a) 660 (b) 6600 (c) 66
  4. 4.√24 to 1 decimal place? (a) 4.9 (b) 4.6 (c) 4.7 (d) 4.8
  5. 5.Best estimate of 5826 ÷ 64? (a) 97 (b) 970 (c) 9700
  6. 6.Best estimate of 2159 ÷ 72? (a) 3100 (b) 310 (c) 31
  7. 7.√26 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.3 (d) 5.4
  8. 8.√30 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.8 (d) 5.7
  9. 9.Best estimate of 3216 ÷ 37? (a) 8000 (b) 800 (c) 80
  10. 10.√42 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.7 (d) 6.6
  11. 11.√34 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 5.7 (d) 5.6
  12. 12.√61 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.7 (d) 7.8
  13. 13.Best estimate of 627 ÷ 28? (a) 210 (b) 2100 (c) 21
  14. 14.√74 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.8 (d) 8.7
  15. 15.√58 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.9 (d) 7.8
  16. 16.Best estimate of 4494 ÷ 71? (a) 640 (b) 6400 (c) 64
  17. 17.√32 to 1 decimal place? (a) 5.6 (b) 5.8 (c) 5.9 (d) 5.7
  18. 18.Best estimate of 2266 ÷ 42? (a) 570 (b) 5700 (c) 57
  19. 19.Best estimate of 3090 ÷ 78? (a) 3900 (b) 390 (c) 39
  20. 20.Best estimate of 3957 ÷ 52? (a) 79 (b) 7900 (c) 790
  21. 21.Best estimate of 2704 ÷ 56? (a) 45 (b) 450 (c) 4500
  22. 22.Best estimate of 6089 ÷ 78? (a) 7600 (b) 760 (c) 76
  23. 23.Best estimate of 1405 ÷ 42? (a) 350 (b) 35 (c) 3500
  24. 24.√82 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.9 (d) 9.2
  25. 25.Best estimate of 2684 ÷ 44? (a) 67 (b) 6700 (c) 670
  26. 26.√66 to 1 decimal place? (a) 8.2 (b) 7.9 (c) 8.0 (d) 8.1
  27. 27.Best estimate of 4142 ÷ 86? (a) 4600 (b) 460 (c) 46
  28. 28.Best estimate of 4549 ÷ 81? (a) 57 (b) 5700 (c) 570
  29. 29.Best estimate of 6880 ÷ 82? (a) 8600 (b) 86 (c) 860
  30. 30.Best estimate of 5274 ÷ 71? (a) 7500 (b) 750 (c) 75
  31. 31.Best estimate of 1178 ÷ 51? (a) 240 (b) 2400 (c) 24
  32. 32.√89 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.3 (d) 9.4
  33. 33.Best estimate of 4684 ÷ 78? (a) 59 (b) 5900 (c) 590
  34. 34.Best estimate of 2161 ÷ 24? (a) 10800 (b) 1080 (c) 108
  35. 35.Best estimate of 1675 ÷ 52? (a) 340 (b) 3400 (c) 34
  36. 36.Best estimate of 2584 ÷ 62? (a) 430 (b) 43 (c) 4300
  37. 37.√44 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.7 (d) 6.6
  38. 38.Best estimate of 7321 ÷ 89? (a) 810 (b) 81 (c) 8100
  39. 39.Best estimate of 6013 ÷ 69? (a) 8600 (b) 860 (c) 86
  40. 40.√92 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.7 (d) 9.4

Answer key

  1. 7.9
  2. 39
  3. 66
  4. 4.9
  5. 97
  6. 31
  7. 5.1
  8. 5.5
  9. 80
  10. 6.5
  11. 5.8
  12. 7.8
  13. 21
  14. 8.6
  15. 7.6
  16. 64
  17. 5.7
  18. 57
  19. 39
  20. 79
  21. 45
  22. 76
  23. 35
  24. 9.1
  25. 67
  26. 8.1
  27. 46
  28. 57
  29. 86
  30. 75
  31. 24
  32. 9.4
  33. 59
  34. 108
  35. 34
  36. 43
  37. 6.6
  38. 81
  39. 86
  40. 9.6

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths